The present disclosure relates generally to systems for dispensing liquid adhesive. More particularly, the present disclosure relates to the retaining system for solenoid assemblies used to actuate dispensing modules.
Hot melt dispensing systems are typically used in manufacturing assembly lines to automatically disperse an adhesive used in the construction of packaging materials such as boxes, cartons and the like. Hot melt dispensing systems conventionally comprise a material tank, heating elements, a pump and a dispenser. Solid polymer pellets are melted in the tank using a heating element before being supplied to the dispenser by the pump. Because the melted pellets will re-solidify into solid form if permitted to cool, the melted pellets must be maintained at temperature from the tank to the dispenser. This typically requires placement of heating elements in the tank, the pump and the dispenser, as well as heating any tubing or hoses that connect those components. Furthermore, conventional hot melt dispensing systems typically utilize tanks having large volumes so that extended periods of dispensing can occur after the pellets contained therein are melted. However, the large volume of pellets within the tank requires a lengthy period of time to completely melt, which increases start-up times for the system. For example, a typical tank includes a plurality of heating elements lining the walls of a rectangular, gravity-fed tank such that melted pellets along the walls prevents the heating elements from efficiently melting pellets in the center of the container. The extended time required to melt the pellets in these tanks increases the likelihood of “charring” or darkening of the adhesive due to prolonged heat exposure.
Hot melt dispensing systems typically utilize a solenoid valve mounted to the system to actuate the dispensers between an open position and a closed position. Solenoid failures are one of the most common failures on hot melt dispensers. However, solenoid mountings require either multiple fasteners to hold the solenoid assembly in place, or require the user to perform multiple actions, such as pulling in one place and pushing in another, to attach and detach the solenoid assembly.